Compost is decomposed organic matter - ideally a well-digested, rich, black, sweet-smelling, crumbly, soil-like substance, full of the nutrients originally extracted from the soil by plants.
After a plant or animal dies, bacteria in soil go to work to decompose the remains - slowly. To speed up the process, we can build a compost pile - to create the ideal conditions for specific bacteria. The better we manage these conditions, the faster the bacteria will get to work!
A compost pile can use three kinds of bacteria
- Psychrophilic bacteria when you first build the pile, which like best temperatures between 0C and 15C. Given enough air, moisture, and food, these bacteria will be very happy, eat and reproduce - at an amazing rate in ideal conditions! This builds heat. A compost pile of minimum size (1 metre x 1 metre x 1 metre) will retain the heat generated.
- As the heat in the centre builds to between 15 and 40C, mesophyllic bacteria get to work, eat and reproduce - and generate more heat!
- Once the heat of the pile reaches 40C, thermophilic bacteria will get to work - and you will have a fast, efficient, hot compost heap. As the food and water start to run out, the thermophilic bacteria slow down, and your pile starts to cool off. Turn it, so that you add more moisture, air, and food to the centre and wake up the thermophilic bacteria again. At this temperature, many weed seeds, pest larvae and eggs, and disease spores are killed off - thoroughly cooked!
Eventually, the pile will not be able to remain over 40C, and the mesophyllic will take over again. Other micro-organisms now join in, and as the composting process continues, so will larger creatures, including centipedes, millipedes, beetles, and earthworms.
To get an idea of the passions aroused by composting, visit these sites:-